Fire alarm



A ril23, 1940. JLLAFLEUR 2,198,410

FIRE .ALARM Filed Feb. 9, 1938 f05ephL.Lafilew INVENTOR.

ATTORNEYS.

Patented Apr. 23, 1940 UNITED STATES PATENT OFFICE,

1 Claim.

This invention relates to fire alarm apparatus and it is designed more especially for use in connection with an ordinary door bell circuit whereby, in the event of a fire, the door bell will be sounded so as to give an alarm to the occupants of the structure in which it is located.

A further object is to provide a fire alarm apparatus which is simple, compact and efficient and can be installed readily in a door bell circuit in the same manner as an ordinary pushbutton.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts hereinafter more fully described and pointed out in the claim, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

In the accompanying drawing the preferred form of the invention has been shown.

In said drawing Figure l is a section through the apparatus constituting the present invention, its connections with a door bell circuit being indicated in diagram.

Figure 2 is a section on line 2--2, Figure 1.

Referring to the figures by characters of reference i designates a base plate having end ears struck outwardly therefrom as indicated at 2. These ears are adapted to extend into and to be bolted or otherwise fastened to a shallow housing 3 which can be formed with apertures 4.

Secured to the base plate I adjacent to one end thereof is a block 5 of insulating material carrying a contact pin 6 having a binding post 1 to which is adapted to be connected one wire of the electric circuit.

Spaced ears 8 are struck inwardly from the plate l and extending between these cars is one end portion of a spring strip 9, said end portion being bent to form a hook is which straddles one of the ears. A binding post H is secured to the spring strip and is adapted to be secured to another wire of the electric circuit with which the device is to be used.

A stop ear I2 is struck inwardly from the plate I adjacent to the contact pin 6 and constltutes an abutment for spring 9 when it is pulled back away from contact 6 and out of normal position, as shown in Figure 1.

An ear I3 is struck from the base I at a point remote from contact 6 and is adapted to be engaged by a looped cord 14 while another looped cord I5 is adapted to be connected to the spring 9 at a point between the ends thereof, as shown. Loop-ed cord I6 is extended through an aperture I6 in one end of a plate I! while looped cord I5 is extended through an aperture K8 in another plate I9. The two plates are placed face to face with an interposed soft solder 29 formed of an alloy which will melt in a temperature of approximately 120 F. Thus under normal conditions the two loops I4 and I5 are held under tension and the spring 9 is pulled back against stop 12 so that it will not engage the contact 6.

A device such as herein described is adapted to be sold as a complete article of manufacture for installation in an ordinary door bell circuit. Such a circuit has been indicated in Figure 1 Where the bell has been shown at 2%, the ordinary push-button at 22, the battery at 23, and the wires at 24 and 25 respectively. When it is desired to install this invention a wire 26 is extended from wire 25 to the binding post II and another wire 21 is extended from wire 24 to the binding post 1.

The casing formed of the parts I and 3 is then placed at a desired location in the structure and obviously the circuit closer 9 will remain inactive unless subjected to a temperature of more than 120 F. When such a temperature is reached, the solder 20 will be softened so as to release the plates l1 and I9 from each other. Thus the restraint upon spring 9 will be removed and said spring will shift automatically against the contact 6 and close the circuit to the bell 2|.

It will be noted that this device at no time interferes with the proper functioning of the door bell. Obviously any desired number of these devices can be set up in the door bell circuit, they being located at various points in the structure to be protected thereby.

It will be noted that cords l4 and i5 are used for supporting the plates in the housing. These cords are combustible so that under certain conditions they will be destroyed by fire, thereby releasing the spring should the fusible connection between the plates fail to work.

Although the bell circuit has been shown and described as including a battery, it is to be understood that a transformer could be substituted for the battery.

What is claimed is:

A circuit closer for installation in a signal circuit, including a casing, a contact within and insulated from the casing, a pair of ears struck inwardly from the casing, a spring strip of conducting material extending between and anchored to the ears, there being a slot in the casing through which the free end of the spring strip is extended and within which it is mounted to move, a stop ear struck from the casing adjacent to the opening for limiting the movement of the spring strip in one direction, another ear struck inwardly from the casing, a plate in the casing, a combustible anchoring connection between said plate and the last named ear, a second plate lapping the first named plate, a fusible connection between the plates for holding them normally against relative movement, and a combustible connection between the second plate and the spring strip for holding said strip normally against its stop ear and away from the contact, said spring strip when released by separation of either of the combustible means or the plates being shiftable against the contacts so as to close an electrical connection between said contacts and the casing.

JOSEPH L. LAFLEUR. 

